Control means for high speed printing apparatus



' Sept. 10, 1957 L. ROSEN ETAL 2,805,620

CONTROL MEANS FOR HIGH SPEED PRINTING APPARATUS Filed Dec. 15, 1951 2 Sheets-Sheet l /%WA)P0 59620144 14 0 f4) QW/VA/i/ Sept. 10, 1957 L. ROSEN ETAL CONTROL MEANS FOR HIEGH SPEED PRINTING APPARATUS Filed Dec. 15, 1951 2 Sheets-Sheet 2 p, M m M, w 0 mM/ i a d M AW/Av 0 a p, H M

United States Patent CONTROL MEANS FOR HKGH SPEED PRINTING APPARATUS Leo Rosen, Arlington, and Howard C. Barlow and Ray ll. BowmamFalls Church, Va.

The invention described herein may be manufactured and .used by or for the Government for governmental purposes Without the payment of any royalty thereon.

Thisinvention is in printing devices and more particularly'is a simplified high-speed printer.

The principal object of this invention is to provide a high-speed on-the-fiy printer having relatively few inter-* mittently moving parts and, thus, few inertia problems,

with resulting economy of maintenance.

Another object is to provide a printer of the type mentioned without sliding contacts.

A further object is to provide a printer wherein magnetically-generated impulses are utilized to control the printing of desired characters.

An additional object ,is to provide in an apparatus .of the nature mentioned a rapidly-moving .indicia-bearing member and an impulse generator synchronizedtherewith with means for utilizing a particular impulse identified by the depression of a.key, for example, for causing the desired printing operation'to occur.

Another-specific object is tocontrol a printing operation by counting periodic pulses generated after a predetermined instant identified by the depression of a key on a keyboard.

Other objects will be apparent from a reading ,ofxthe following specification and claims.

in the drawings:

Figure 1 is a simplified diagrammatic view of the principal features of one embodiment of .our invention, together with a detailed showing of a novel switching arrangement which may be utilized;

Figure 2 is a similar View of a modified'form of our invention; 2

Figure 3 is a showingof a modified impulse generator for use with our invention; and

Figure 4 is a fragmentary showing of a further modified impulse generator.

Referring to the drawings and specifically to Figure 1, the printing device of our invention can be seen .to comprise a motor 10 of any convenient description, operated from a powersource (not shown), driving a shaft 21, a plurality of print wheels 11, 12, and 13, a print hammer l4, electrically actuated by means of a coil 15, and certain electrical control elements which will :be described below.

The print wheels have indicia,'for example, Arabic numerals" 0 through 9, engravedjor otherwise formed at regular intervals about their peripheries. While'the print wheels have been identified as separate discs (which they may, in fact, be), they may also take the form ofan in- .tegral cylinder with a number of circumferential arrangementsvof indicia thereon in regular parallel relation to each othe A y number of print wh e s may .he used. th onlybeging shown for purposes ,of simplify-ing the descriptiq e 'a a -pr c he e w l u lly e thirty to fi ty suah heel No paper. or ribbon or feeding mechanisms therefor are shown in the drawings, as virtually any conventional arrangement of such elements can be utilized with our invention, but it will be understood that ordinarily an inked ribbon is moved adjacent the print'wheels, and a paper is fed between the ribbon and the print hammers. When hammer 14 (for example) is actuated,itrotates about the pintle 16 (which is supported in any convenient fashion), and the head 17 thereof momentarily forces the paper against the ribbon and the ribbon against a character on wheel 11 to accomplish a printing operation. A spring 20, secured to some part-of the printer housing, is-provided for retracting the hammer as soon as winding v15 is deenergized.

In accordance with known techniques, the print hammers are preferably adjusted so that they will not normally touch the wheels. When, however, a hammer is properly actuated, it will, at the end of its stroke, bend slightly to accomplish a printing operation. In order-to achievetthe best performance, the mass, inertia, and resonance of the hammer structure are calculated relative to the build-up and decay time of the magnetic field, the strength of the retracting spring, etc., and the magnetic field and the retracting spring are utilized for damping as well as for driving. These features do not enter -.into the invention herein described and claimed.

Located about the shaft-21 are a number of windings,

as 30, mounted in a suitable support 30. The exact'nurnber of such windings will ordinarily be the same as the number of indicia on each type wheel, and the'windings are carefully spaced so that their angular positions are identical with those of the print wheel characters. (Additional coils may, of course, be provided to furnish timing pulses, etc., if desired.) Within the annulus of coils and mountedron shaft 21 is a member '35, formed of some magnetizable material, having a toe or extension '36. This extension, particularly, and the Whole member may hereinafter be referred to as a rotating pole piece. Eachof the coils 30 is functionally associated with a specific numeral on a print. wheel. For the purposes of this description, each coil, therefore, bears a notation, that is, a number of 0 to 9, corresponding to one of the characters on the print roll.

Pole piece '3536 is carefully oriented with respect to its surrounding windings and the print roll so that (ignoring for a moment a slight delay it may be desirable to interpose in the system) at the instant that the pole piece passes coil 2, for example, the numeral 2 of the print wheel 11 passes adjacent the print hammer 14.

In order to control print hammer 14 through its winding 15, a lead, as 31, is taken from each of the coils 30, and each lead is terminated in a fixed switching contact, as 32. Movable contacts, as 33, are provided therefor to complete the required circuits. Although manual switches are shown,

in practice, electrically-operated or electronic switches may be used depending upon circumstances. It should be understood that the coils 30 at the lower portion of Figure l are the same coils shown in the mechanical illustration in the upper portion of the figure.

At this point it may be well to note that, just as only three print wheels are shown, for simplification of description, so only one print hammer (14) is shown, and one group of switches 32-33. In practice, there must be a hammer and control, with switch arnay (32-63), for each wheel. A single annulus of windings 30, together with its pole piece, will serve all hammers although separate impulse generators may be used for each one, if desired.

Switches 32-33, no matter how actuated, are operated in response to a keyboard, punched tape, punched'card,

these are, obviously, representative computer, or some similar instrumentality, which determines in the first instance the character to be printed.

The switch output is fed into a common line 45, and thence to a further switch, the preferred embodiment of which is a thynatron 46 normally held in an off or nonconducting condition by means of negative battery 37. The plate circuit is shown provided with a switch 38 and a source of positive potential 38'. This last-mentioned switch, also in practice, may be replaced by electronic or mechanically-operated means.

The plate circuit of the thyratron 46 includes a condenser 39 and the winding 15 of print hammer 14.

The circuit components are so selected, as just men- I tioned, that normally tube 46 does not conduct. With switch 38 closed, a predetermined charge accumulates across condenser 39, while negligible current flows through winding 15, due to the limiting effect of resistor 40, and hammer 14 does not operate.

When a switch 32--33 is closed, and a pulse occurs on line 45 due to a coaction of a coil 30 and pole piece35-36 (this pulse, in the embodiment being described, being positive), the initial negative bias of tube 46 is overcome,

the tube conducts, condenser 39 discharges therethrough,

and current flows in winding 15, actuating hammer 14, to clause a printing operation to be accomplished. The discharge of condenser 39 drops the plate voltage of tube 46, and tube 46 ceases to conduct.

The circuit to condenser 39 can be opened by means of switch 38, and recharging of condenser 39 thereby prevented. This action will prohibitfurther printing as pole piece 36 reaches the selected coil on successive revolutions. A hand'operated switch, such as that illustrated, will in some cases be much too slow in actual practice and should herein be considered illustrative only.

In the embodiment of the invention shown in Figure 2, a counter is interposed between the impulse-producing means and the thyratron switch. The counter is not illustrated in detail nor will it be specifically described since any of many conventional devices may be employed. In the apparatus to be described, it is essential that the capacity of the counter be the same as the number of characters on the type'wheels, but the operation could easily be modified to eliminate even this requirement. The counter may, in other words, he mechanical, electrical, or electronic, and count in the decimal, binary, or other convenient system. I

In this form of the invention, the impulse generator is essentially like that shown in Figure l, but the windings 50 (analogous to the windings 30 of Figure 1) are connected together. The pole piece 51-52 is identical with that already described. No individual switches such as 32-33 (Figure 1) are employed. In other words, in this form of the invention, with motor 60 in operation and pole piece 51--52 rotating, consecutive regularly-spaced pulses are fed into line 61;

Adjacent the pulse generator just described is another somewhat similar arrangement including a single winding 65 and a pole piece 6667; the winding and the projection are oriented so as to produce a pulse in the position of the print roll. This last-mentioned pulse-producing means serves to energize a gate circuit 70 whenever the print roll and the counter 71 are at 0, provided, however, switch 62 is closed. The gate circuit, it will. be understood, will permit pulses from the pulse generator 50--52 to reach the counter 71 only after it has been energized.

The exact method of operation of this form of the invention will depend upon the exact number of characters on the type wheels and, perhaps, upon other circumstances. Assuming, however, that ten characters are involved (as before) and assuming that gate circuit 70 is normally nonconducting, the apparatus functions in the following manner: the pressing of a keyon a keyboard or some other presentation of intelligence, meaning that 6 (for example) is to be printed, presets counter 71 to the reciprooal (base of 6, that is, 4; switch 62 is then closed so that, when pole piece 67 next passes winding 65, the resulting pulse will be transmitted to gate 70 to cause it toassume its conducting condition.

This means that, starting with the 0 position, a succession of regular pulses, each representing a position of the type roll, is fed to counter 71. If, as is assumed, the capacity of the counter is ten, six pulses will be fed into the counter, after the gate is opened, before the counter reaches its full capacity, and produces an output pulse. At this instant, of course, the several print wheels are in their number 6 positions, and the output pulse of the counter energizes the proper print hammer, as earlier described.

After counter 71 produces an output pulse, switch 75 must be opened to prevent further printing until a desired further character can be determined. Switch 62 also must be reopened; both switches are shown as manually operable. In practice, they will usually be replaced by electronic means actuable by the output of the counter.

Obviously, an essential similar result would be achieved by entering the number to be printed in counter 71 (rather than a reciprocal of such number) if the order of appearance under the hammer of the printing elements were reversed.

The operation of the printer proper and the thyratron switch is just as was earlier described in connection with Figure l. Resistor 81 and condenser 82 represent a convenient form of coupling'between the pulse-producing elements of the apparatus and switch tube 80; other couplings may be employed.

The detail of Figure 3 represents a modified form of impulse generator. Broadly,.its organization is similar to that of the generator already. described, but the annular array of coils of Figures 1 and 2 is replaced here by an annulus of photosensitive cells 9.0, and the pole piece of this figureis a rotating light source 91 provided with foscusing means 91' (not shown in detail) for forming the light thereof into a beam or pencil of restricted extent. The photocells are preferably also provided with masks 90 having small openings therethrough.

Current for light source 91 is provided by battery B through suitable lines and brushes 92 and 93 which ride on the slip rings 95 and 96, respectively.

The restricted size of the beam from source 91 and the photocell masks 90 assure the generation of short, sharp pulses as the light source rotates. These pulses are used in described in connection with Figures 1 and 2.

Figure 4 illustrates: a further. modified impulse generator comprising a single winding supported in any desired fashion adjacent a pole piece 101 having a plurality of impulse-generating elements 102. Member 101-102 is mounted on a rotating shaft 103. This embodiment of the invention may be substituted for the impulse generator of Figure 2, in which case winding 100 produces a regular succession of pulses on line 61, with the pulses being prevented from reaching counter 71 except after gate 70 has been made conducting by means of a pulse from the gate-actuating structure 65-67.

As has been hereinbefore mentioned, the printer of our inventionmay be operated as end equipment with various kinds of intelligence-producing input devices. The printer may, of course, bearranged to advance from line to line after a predetermined number of characters have been printed or after a line has been filled, this depending upon individual requirements but in no case representing a part of our invention but instead expedients of the prior art.

Each print. hammer, as has been stated, is provlded with its own control of the nature described, and the hammers workin conjunction to print a line of desired length, Inmany applications it will be found that, because oftheorder in'which indicia determinations are made, an entire line cannot be printed during a single rotation of the print roll.- Experience has, in fact, shown that a line of, perhaps, thirty characters will require an average of about 1.2 rotations of the print roll. Since, however, time inormally mustbe allowed for paper advance, hammer movement, etc., it is convenient to allow two complete rotations of the print roll for each line of the length indicated. This still permits printing at a rate of about fifteen operations per second.-

It was earlier mentioned that it may be desirable to provide a slight disorientation between the several coils of an impulse generator and the corresponding characters of the print wheel associated therewith. This may be unnecessary in some situations if speeds are not substantial, but, otheiwise, will correct for the slight delays involved in pulse buildup, flux buildup, hammer movement, etc. To this end, the pole pieces are made rotatably adjustable upon their shafts; alternatively, the entire aggregation of windings 50 may be rotated in an appropriate mounting.

The foregoing description has been directed to the preferred embodiment of our invention, and many modifications will readily suggest themselves. For the true scope of the invention, therefore, reference should be had to the appended claims.

We claim:

1. In a printing device including a substantially continuously moving carrier having n indicia spaced thereupon and means for forcing a paper toward selected ones of said indicia when actuated to accomplish printing operations, and means for actuating said forcing means, means for controlling said actuating means comprising an annulus of n windings constituting parts.of magnetic circuits, a pole piece rotating with said carrier to pass said windings and thereby to generate pulses in a line connected thereto the timing of the pulses being substantially identical with the timing of the movement of said indicia relative to said forcing means, means for varying the phasing of said pulses relative to the rotation of said carrier, and means for selectively connecting said windings to said actuating means.

2. In a printing device including a substantially continuously rotating print wheel having n indicia spaced thereupon and a hammer for forcing a paper against selected ones of said indicia when actuated to accomplish printing operations, and means for actuating said hammer, means for controlling said actuating means comprising an annulus of windings constituting parts of magnetic circuits, a pole piece rotating with said Wheel to pass said windings thereby to generate pulses in a ilne connected thereto the timing of the pulses being substantially identical with the timing of the movement of said indicia relative to said hammer, and means for selectively connecting said windings to said actuating means.

3. In a printing device including a substantially continuously rotating print wheel having n indicia spaced thereupon and a hammer for forcing a paper toward selected ones of said indicia when actuated to accomplish printing operations, and means for actuating said hammer, means for controlling said actuating means comprising an annulus of n windings constituting parts of magnetic circuits, a pole piece rotating with said wheel to pass said windings and thereby to generate pulses in a line connected thereto the timing of the pulses being substantially identical with the timing of the movement of said indicia relative to said hammer, means for vary ing the phasing of said pulses relative to the rotation of said print wheel, and means for selectively connecting said windings to said actuating means said last-mentioned means comprising an electron tube having a conducting condition and a nonconducting condition, a plate circuit for said tube, means for connectingsaid actuating means to said plate circuit, a condenser between said plate circuit and said actuating mean, means dependent upon said pulses for varying the conductivity of said tube and 6 7 thereby the discharge patlr of said c'ondens'erto deliver a pulse to said actuating means; i

4. In a printing device including a substantially continuously rotating print wheel having n indicia spaced thereupon and a hammer for forcing a paper toward selected ones of said indicia when actuated to accomplish printing operations and means for actuating said hammer, means for controlling saidactuatingmeans comprising an annulus of n windings constituting parts of magnetic circuits, a pole piece rotating with said wheel to pass said windings and thereby to generate pulses in a line connected thereto the timing of the pulses being substantially identical with the timing of the movement of said indicia relative to said hammer, a pulse-actuated counter, an input circuit for said counter said input circuit including said line and means for determinedly producing a gate to permit the delivery of said pulses to said counter, circuit means for delivering an actuating current to said actuating means when a predetermined total is counted by said counter,.'and means for presetting said counter.

5. In a printing device including a substantially continuously rotating print wheel having n indicia spaced thereupon and a hammer for forcing a paper toward selected ones of said indicia when actuated to accomplish printing operations, and means for actuating said hammer, means for controlling said actuating means comprising a winding constituting a part of a magnetic circuit, a pole piece rotating with said wheel to pass said winding and thereby to generate pulses in a line connected thereto the timing of the pulses being substantially identical with the timing of the movement of said indicia relative to said hammer, a pulse-actuated counter having an input circuit and an output for counting to a predetermined total and then producing a pulse at its output said input circuit including said line and means for determinedly producing a gate to permit the delivery of said pulses to said counter, and circuit means energized by an output pulse for delivering an actuating current to said actuating means.

6. In a printing device including a substantially continuously rotating print wheel having indicia spaced thereupon and a hammer for forcing a paper toward selected ones of said indicia when actuated to accomplish printing operations, and means for actuating said hammer, means for controlling said actuating means comprisinga winding constituting a part of a magnetic circuit, a pole piece rotating synchronously with said wheel and cooperating with said winding to generate a succession of pulses the timing of said pulses being substantially identical with the timing of the movement of said indicia relative to said hammer, a pulse responsive counter having an input circuit, an output, and means for delivering a pulse to its output after a predetermined count, said input circuit including means for determinedly producing a gate to permit the delivery of said pulses to said counter, and circuit means energized by a said output pulse for delivering an actuating current to said actuating means.

7. In a printing device including ,a substantially continuously rotating print wheel having indicia spaced thereupon and a hammer for forcing a medium toward selected ones of said indicia when actuated to accomplish printing operations, and means for actuating said hammer, means for controlling said actuating means comprising a winding constituting a part of a magnetic circuit, a pole 7 piece rotating in proximity to said winding to generate in said magnetic cincuit a succession of pulses the timing thereof being substantially identical with the timing of the movement of said indicia relative to said hammer, said controlling means including an electron tube having a conducting condition and a nonconducting condition, and means dependent upon said pulses for varying the conductivity of said tube thereby to operate said actuating means.

(References on following page) References Cited in the file of this patent H UNITED STATES PATENTS 4 Pierce May 16; 1933 Carroll July 4, 1933 Lake July 10, 1934 Buhler Sept. 3, 1935 Buhler Feb. 11, 1936 Bryce -1 Sept. 1, 1936 Rabenda Oct. 30, 1951 I FOREIGN PATENTS Great Britain May 19, 1927 

